Simplified numerical modeling and simulation of compositelaminated plates by the variational asymptotic method

This paper develops a simplified model for composite laminated plates by the variational asymptotic method (VAM) in order to efficiently analyze the nonlinear, one-way couples problem. It deduced the 3D energy expressions based on the decomposition of rotation tensor (DRT). The 3D laminated plate model is decomposed into a 2D plate analysis and a non-linear 1D analysis along the normal direction. The approximate energy after dimensionality reduction was deduced and converted to a form of reissner model. The 3D field recovery relations are provided to obtain accurate stress distribution through the thickness direction. The cylindrical bending example of 4-layer composite plate shows that the 3D stress fields recovered by this theory have better accuracy than those by the classic laminated theory (CLT), which indicates the validity of this model.     

Numerical Prediction of Frequency of Delaminated Advanced Grid Stiffened plate

The paper aims to investigate natural frequency of delaminated advanced grid stiffened composite plates by hump resonance method.The composite laminated plate element and the rib element are adapted to simulate the laminated plate and the ribs.Based on the composite laminated plate and beam element model considering first-order shear effect,a damping model on the basis of Rayleigh damping model in conjunction with Adams' strain energy method(MSE) and a Hertz nonlinear dynamic contact model to avoid the overlap and penetration phenomenon between the upper and lower sub-laminates at the delaminated region.A numerical analysis method of dynamic response for the delaminated composite plates is carried out by precise time-integration method,and then the natural frequencies are achieved when the dynamic deflections reach the hump peak.For the frequency-domain analysis provided in the former research papers,it is a difficult problem to avoid the embedded phenomenon in the mode shapes at the delamination zone,while in the current time-domain analysis,the embedded phenomenon can be successfully overcome by using nonlinear contact model.By vibration excitation test,the specimens were excited by different excited frequency and the amplitude frequency response characteristics obtained are used to extract the frequency.The extracted frequencies of the narrow delaminated composite plates measured,which agrees well with the predicted natural frequencies.     

Preliminary Optimization of Partial Single layer Reticulated Shells Based on Uniform Design[JP]

Size, shape and topology optimizations are involved in the structural design of partial single layer reticulated shells. To meet the requirements of computation efficiency during preliminary design, a uniform design method was adopted to achieve multi level optimization. Only existing software packages for reticulated shells were used in the experiment design. By regressing the computing data, approximate functional relations between the indexes (steel weight, deflections, basic frequency, and minimal nonlinear buckling load) and variables (rise of the shell, single layer area, and design stress ratio for single layer members) were obtained. The best combination of the variables was acquired by solving a simple programming problem. Comparative design of a multipoint supported hexagonal reticulated shell verified the efficiency and reliability of this approach.     

ANALYSIS AND PROGRAM FOR CHUNK AND STIFFENED SHELL STRUCTURES BY FINITE ELEMENT METHOD

The improved isoparametric shell element and the biased Isoparametric beam element are applied to the composite structures which consist of cubic chunks and stiffened shells. A flexible and practical method is found for this type of composite structure. The example shows that the theory and program are efficient.     

Design of Double Layer Torsional Reticulated Shell Using Back- Propagation Neural Network

In this paper artificial neural networks are used for design of large span double layer torsional reticulated shell. The torsional reticulated shells with spans varying between 50.0 - 80.0m are considered, Back -propagation algorithm is employed for training efficient neural networks for evaluation of the maximum deflection, weight and design of double layer torsional reticulated shell. A special method is developed for data ordering to reduce the nonlinearity of data and to increase the speed of training. This approach also provides the necessary stability. It shows that it is feasible to design double layer reticulated shell with artificial neural networks.     

Effects of Stitcing on the Buckling Strength of Stitched Composite Laminates

A theoretic model is proposed based on the mechanism of the buckling failure of the stitched composite laminates containing delaminations. The buckling strength of the stitched composite laminates under the in-plane compressive load is predicted. The critical percentage elongation of the stitching thread is taken into account as a control parameter of the buckling failure. The energy method is used to calculate the buckling strength of the stitched composite laminates, and the minimal potential energy is used to calculate that of the unstitched composite laminates. The result shows that the buckling strength of the stitched composite laminates is larger than that of the unstitched composite laminates. The effects of stitching technical parameters such as the stitch thread diameter, stitch step and stitch space on the stitched composite laminates are also analyzed.     

食品加工剩余物板栗壳的利用研究进展

为了更好地对食品加工剩余物板栗壳进行开发利用,促进节能减排,综述了国内外最近20年在板栗壳资源化利用方面的研究进展,发现现有研究涉及将板栗壳作为生物吸附剂用于重金属污水处理、作为基质用于食用菌栽培和作为原料用于活性炭制备,以及从中提取天然色素用于食品着色和纺织品印染等方面,但这些研究并不系统,今后还需对板栗壳色素进行安全性评价,补充其毒理学和代谢方面的数据。板栗壳对重金属的吸附量偏低,有待于进一步通过理化改性提高其吸附性能,提取过色素的板栗壳残渣可进一步作为原料用于制备活性炭,以达到循环利用。     

基于Workbench杏壳力学特性分析

为提高杏核的破壳质量,对杏核壳体的力学性能进行研究。考虑到杏核表面有凸起的棱筋及壳体不同区域厚度不同对力学特性的影响,通过威布三维Reeyee扫描仪对1/2赛买提杏核壳体进行扫描,利用SpaceClaim软件对杏核壳进行模型修复,得出杏核壳体的三维分析模型;运用ANSYS Workbench对1/2杏核壳体进行3种方式加载云图分析,得出最佳的破壳方式,然后通过试验验证模型分析的准确性。结果表明：赛买提杏核沿不同方向施压所需的破碎力有显著差异,其中沿Y 轴方向所需破碎力最大,为856 N,变形量为2.48 mm,杏仁破碎率为0;沿X=Z 轴方向所需破碎力最小,为398 N,变形量为0.41 mm,杏仁破碎率为21.8%;沿X 轴方向施压所需的破碎力为426 N,变形量为1.08 mm,杏仁破碎率为0。验证试验结果与模型分析的结果一致。因此,通过扫描仪建模更能准确反映杏壳的表面特征,相对于Y、X=Z 轴,沿X 轴方向施压更合适。本文可为杏核破壳机械的设计提供参考依据。     

Numerical Simulation for Dynamic Response of Large Space Cylindrical Reticulated Shell under Internal Explosion by Ritz POD Method

A numerical simulation test of the internal explosive loading on large space structure was carried out by employing algorithm ANSYS/LS DYNA.An appropriate model was established for calculating the dynamic responses of the large space cylindrical reticulated shell under inner blast loading based on the proof of correctness and reliability of the model and parameters selection.Combining the Ritz vibration mode superposition method with the Proper Orthogonal Decomposition (POD) method, the problems of spatiotemporal asynchrony of shock waveforms and pressure distributions on large space structure surface were solved and the calculation for dynamic response of large space structure was reduced and simplified.Furthermore, the numerical simulation of dynamic responses was carried out.And the influence of the ratio of rise to span and the explosive position on the dynamic responses of the structure was studied.It was found that the calculation model was suitable for the dynamic response analysis of the large space cylindrical reticulated shell under internal explosion and the cylindrical reticulated shells with bigger ratios of rise to span were stronger in the capacity of anti explosion.In general, the damages to the large space structure caused by eccentric blast shock waves were more serious than that caused by central explosion.And it was the most disadvantageous to the edge components of the structure.The more attention should be paid to the anti explosion capacity of the support areas and the edge components while designing the shells.     

Spawning of two Pomatoschistus species (gobbidae) in relation to nest availability and depth: A field experiment

The spawning of two sympatric gobiid fishes, the sand goby Pomatoschistus minutus and the common goby Pomatoschistus microps was investigated in relation to nest availability and depth. In two field experiments, carried out in the northern Baltic proper during summer, empty shells of the mussel Mya arenaria were divided into three size groups and provided as spawning substrates. The shells were set out at different depths and at different densities.Spatial habitat partitioning by depth was found. The sand goby preferred the deeper bottoms (2.8 m) and the common goby spawned only in areas shallower than 1 m. The spawning of the two species was separated in time by about 6 weeks with an overlap at the beginning of July. Low water temperatures (∼10°C) in June probably delayed spawning in the common goby.The sand goby preferred the larger shells. The larger the shells, the larger was the number of eggs, i.e. the male potential reproductive success. The common goby preferred the smaller shells, and their potential reproductive success did not show a clear trend with increasing shell size.In both species, the mean number of shells used for spawning increased with increasing substrate density. The maximum nesting density was 21 nests per m² for the sand goby and 20 nests per m² for the common goby. The maximum total density for both species together was 23 nests per m².Interspecific competition for spawning substrates was minimized, as spawning was separated in time and each species preferred different sizes of shell. The intensity of spawning under the shells provided indicates that a lack of suitable substrates limits spawning by both species in this area. The larger sand goby is limited in particular by the lack of larger substrates, and is probably forced to spawn in shallow water when suitable shells do not occur in its preferred depth range.     

2种壳色梨形环棱螺贝壳7种金属元素质量分数比较分析

利用电感耦合等离子体质谱(ICP-MS)对梨形环棱螺(Bellamya purificata)青色和紫色贝壳的7种金属元素质量分数进行了比较分析。结果显示,紫色梨形环棱螺贝壳中铁(Fe)、质量分数显著高于青色贝壳。青色贝壳中钾(K)、镁(Mg)、锰(Mn)的含量显著高于紫色贝壳,钠(Na)、锶(Sr)、锌(Zn)元素含量在两种壳色贝壳中差异不显著。贝壳中Fe含量和K、Mg、Mn的含量呈显著负相关,与Sr、Zn含量的相关性不显著。K、Mg、Mn、Na的四种元素含量呈显著正相关。     

Analysis on Deformation Characteristics of CFG Piles-Gravel Cushion Composite Foundation of the Deep Embedded Secret Passage

In order to investigate the issue in the field of the application of CFG pile application of CFG pile composite foundation technology in deep embedded secret passage of such special structure ground treatment, the settlement deformation of CFG pile composite foundation according to deep are studied and detailed analysis are given in the field test and indoor model test of the gravel cushion with different thickness. Moreover it points out that the cushion compressive deformation must be taken into account, and that the settlement deformation calculation cannot simply consider the amendments of composite foundation. The amendments of cushion deformation must be considered. The effect of the different thickness of cushion on pile-soil stress ratio, total settlement of composite foundation, cushion compression and axial stress of pile body were analysed by using ABAQUS finite element method. Through the analysis of the field test, indoor model test and the numerical simulation of CFG piles-gravel cushion composite foundation of the deep embedded secret passage, a settlement deformation monitoring method has been described and the selection principle of the cushion has determined so as to provide the cushion design basis in the process of composite foundation design.     

Analysis of bearing capability of CFG pile composite foundation

The CFG pile is used to consolidate the foundation in one passenger dedicated line. The field experiments including low strain dynamic testing, bearing capability of single pile and the composite foundation are done, and the bearing capability of composite foundation is calculated, too. The results show that the first and second class piles account for 93.9% and 6.1% respectively, and the bearing capability eigenvalues of single pile and composite foundation are larger than the designed values. The 3D FEM model is established to simulate the stresses of CFG pile top and inter-pile soil changing with load level, and the stress ratio between CFG pile and inter-pile soil is analyzed, too. The following results are got from the calculation results of FEM: 1) the stresses of CFG pile top and inter-pile soil increase with load level, but the increasing rate of the former is larger than the latter; 2) the stress ratio between CFG pile and inter-pile soil increases quickly when the load level is low, and it tends to convergent gradually with load increasing.     

Section Optimization Design of Steel-Concrete Continuous Composite Beams Based on the Finite Element Method

This paper introduces the efficient computer aided design method to optimize the section of steel-concrete continuous composite beams by combining FEM for structure analysis with optimization arithmetic and an efficient shearing force link model of steel-concrete composite beams.The authors established a finite element analysis model,optimization parameter model,optimization mathematics model of steel-concrete continuous composite beams and programs analysis file and optimization control file by using the ANSYS parameter design language. The optimum of the steel-concrete continuous composite beams section is obtained after computing and the optimization result indicates that this method is efficient in optimizing the section of steel-concrete continuous composite beams.So it could be applied extensively in the steel-concrete continuous composite beams section optimization design.     

花生壳研究现状与应用前景分析

花生是我国的主要油料作物和经济作物,花生壳作为其副产物占花生产量的30%左右,花生壳含有多种矿物质及功能成分,在农业生产、食品加工、功能性产品开发等方面有重要的应用价值。但是,目前由于研究技术受限及研究工艺落后,花生壳大部分仍用作饲料和肥料,附加值与利用率低。文章对花生壳的组成成分及其在农业、食品、医药、环保、化工及建筑方面的重要应用及关键技术进行综述及分析。认为深入开发花生壳是未来花生壳利用的重要方向,今后应以工艺优化及技术提升为主,将目前实验室阶段的研究成果形成大规模生产,真正实现循环农业和低碳经济。     

Technique of Surface Reconstruction for Three Dimensional Structure of Chinese Medicihnal Materials

To study the technique of surface reconstruction for Chinese medicinal materials from its cross-sectional images and to display its three dimensional structure.The pattern recognition technique is used to complete the classification and matching of various structures, then the triangle surface approximation is used to produce the 3D surface of the structure.The 3D structure is reconstructed and can be viewed by flexible way based on SGI workstation. The technique and method provided by this paper is contributive to the study and view of various structure of Chinese medicinal materials, and is available to biomedical image processing field.     

A POWER FLOW IN INFINITE VISCOELASTIC CYLINDRICAL SHELLS

In this paper, a solution of propagation wave in an. unconstrained damping viscoelastic cylindrical shells of infinte length under forced vibration is derived by Fourier integral transform techniques. The power flow transmitted along it is analysed. The power flow in an elastic cylindrical shell and that in a viscoelastic shell are compared. The effects of vibration reduction in two viscoelastic shells with different thickness are compared. The results provide a reference for designer in structural vibration reduction.     

3-D Finite Element Analysis of Solidified Shell in Molds for Continuous Casting of Thin Slabs

A three-dimentional thermal elastoplastic contact FE analysis model of solidifiedshell in moulds for continuous casting of thin slabs is set up, based on the known geometry of theshell and the temperature distribution in the shell. We in turn obtain the stress and Strain distributions of the solidified shells formed in lSP and CSP moulds,the gap distributions between the Shellsand the mould walls,as well as the curves of cracking index [1] in the shells,which provides afoundation for the design and control of technical parameturs for continuous casting of thin slabs.     

Computational Simulation on Temperature Field of Slab Continuous Casting Mold

On the core concepts that the distributing of temperature and solidified slab shell in mold are a stable process, a new method to calculate the temperature field in mold has been promoted. Consequently, a coupling model on fluid filed and temperature field in stable state has also been established. The concept of effective heat capacity is introduced to deal with the latent heat source term from phase transformation. During the programming for computation, the dynamic updating method is also applied to simulate the influence of solidification on physical properties. The resolution results of this model are analyzed and compared with the tested thickness of solidified shell from casting broke out slab, which demonstrates the correctness and applicability of this model to the practical continuous casting process. Additionally, the thickness distribution of solidified shell in slab mold are also studied in detail.     

Evaluation on the Damage Evolution of the CRCP+AC Composite Pavement by the Concrete Dameged Plasticity Material Model

In the study on the CRCP+AC composite pavement, the form and distribution pattern of cracks are two important factors influencing the performance and the lifetime of the pavement. The concrete damaged plasticity material model incorporated in the general purpose finite element software named ABAUQS was adopted to describe the mechanical characteristics of the CRC slab. Combining with the temperature field database drawn from the three-dimensional transient heat transfer analysis, the structural damage under the condition of temperature changing is analyzed. The structural damage evolution and the crack behavior of the CRC slab subjected to the thermal-mechanical coupling condition are further analyzed, which suggests that the role of the asphalt concrete surface is not confined only to the scope of improving the performance of the road, its capacity for improving the stress state of CRCP slab is worthwhile to be affirmed. And the reasonable thickness of AC layer should be designed in consideration of the thermal contraction and damage properties of the CRC slab comprehensively.